package company.quna;

import java.util.Scanner;

public class Qu1 {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int m = sc.nextInt();
        int n = sc.nextInt();
        if (m <= n) {
            System.out.println(0);
            return;
        }
        int ans = 1;
        for (int i = m; i > n; i--) {
            ans *= i;
        }
        for (int i = 1; i <= n; i++) {
            ans /= i;
        }
        System.out.println(ans);
    }
}
